The Thai confirmation linked
above is very much like the confirmation a month ago in Vietnam.
Both cases almost certainly involved human to human transmission of
H5N1. The two sets of patients were remarkably similar. In
both instances, the investigation did not begin until the initial cases
had died and no material was available for testing. The
transmission was to a relative, who was caring for the initial
patients, and samples from the care giver were positive for H5N1

The difference in the Thai
cases was not the virus, but the fact that the mother had
no contact with a common source, other than the sick child (the child
became ill in northern Thailand while the mother was in Bangkok).
The aunt, Pranom, did have contact with chickens, but also developed
symptoms after visiting the sick child.

Because this is not really new, it does not signal a new mutation or
the start of a pandemic. A pandemic requires that the human to
human transmission happens easily and frequently. In both
families described above, transmission probably required close contact,
so the transmission does not necessarily signal a pandemic or a new
genetic change.